Water beds are comprised of a frame that carries a liquid filled envelope upon which persons recline. The frame includes a platform having the plan configuration desired, and upstanding side and end walls that confine the overlying mattress to said plan configuration. Flat plastic sheet is employed in the mattress construction, folded and/or seam welded together in a rectangular envelope formation with a fill opening adapted to be closed. The envelope is filled with a heavy liquid such as water, whereby a person reclining is supported by means of flotation as result of displacement.
In a basic water bed mattress as thus far described, there is an absence of means to prevent wave motion, and as a result continued sloshing is a characteristic disadvantage which adversely affects a number of persons who cannot tolerate it. Heretofore, various arrangements for surge control have been proposed, but with complexity and at considerable expense. Also, disturbing movements often result from the change in position of one person to the disadvantage of another, with reference to sleeping partners. Therefore, it is a general object of this invention to provide a simplified means for most effectively damping out wave motion in liquid filled mattresses.
Flotation mattresses of the type here under consideration have been compartmented for flow restriction, the multiplicity of compartments and their attachment to the outside envelope being complicated and costly, it being an object of this invention to provide a detached compartmented means which damps wave motion, all without fastening to the plastic walls of the mattress envelope which heretofore was thought to be necessary. With the present invention, a detached free floating Wave Motion Damper is positioned by flotation within the outside envelope, to carry depending curtains that are comprised of depending cells that control and impede wave motion.
The usual sheet material employed in constructing this wave motion damper is of greater molecular weight than that of the water in which it is to float (some are of lesser weight). Therefore, it is an object of this invention to provide flotation means that suspends said detached compartmented means within the confines of the water bed mattress interior. In practice, a plate of material having lesser weight than the water which it displaces is free to float within each compartment, thereby engaging the top of the compartment to lift the water motion damper within the confines of the mattress interior. Bouyancy of the plates is controlled by varying the displacement thereof, and accordingly the thickness of said plates vary as later described.
Each compartment of the wave motion damper carries a plate of flotation material, it being an object of this invention to utilize said plate to gain a valving action for vertical flow control of water by restricting either or both downward and upward movement of said water. In practice, the plates and/or the top panels of the compartments are ported as will be described.
It is the phenomenon of wave motion in heavy liquid such as water with which the present invention is primarily concerned. In practice, when a person applies his or her weight onto the top surface of a water bed mattress, sudden displacement as is required by flotation of that person causes liquid motion with inertia from the position of that person, in the form of radiating waves moving in all directions. These waves move horizontally and reflect from the sides and end walls of the mattress which are backed by the hard structural retaining walls of the frame, and it is these waves which this invention hastens to dissipate and/or absorb. Accordingly, it is an object of this invention to substantially reduce and to virtually eliminate the direct as well as reflective wave motion in liquid filled mattresses. As will be described, a substantial proportion of the water bed mattress interior is occupied by the said controlling compartments, so as to intercept and impede omni-directional wave motion generated by body displacements of persons applying themselves to or removing themselves from the mattress.
The wave motion which is to be stopped involves the liquid mass of water which is a heavy liquid. As the water is displaced, the fluid particles thereof also move laterally commensurate with the amount of depression, and said fluid particles return again when displacement is removed. The phenomenon of wave motion responds to the proximity or depth of the confining bottom, and the fluid particles transfer motion to adjoining fluid particles, as waves radiate and/or progress, and so on. Consequently, the motion of a given fluid particle is circular and more often or more accurately elliptical. Accordingly, it is an object of this invention to provide a wave motion damper that restricts and damps the circular and/or elliptical fluid movements. It is a feature of this invention that the compartments retard and restrict the said circular and/or elliptical movement effect of the wave motion by which wave energy is normally transmitted.
It is an object of this invention to advantageously utilize hydraulic effects to control the rate and extent of mattress depression, and to this end the liquid control ports are varied in aperture size according to forces applied. Larger port openings are provided for facilitating motion, whereas smaller port openings are provided for restraining motion. A feature is the gradual closure of the flow controlling ports; firstly the closure of primary ports followed by the closure of secondary ports. It is the nature of plastic sheet material to make a fluid tight seal, with flap engagement as herein disclosed; so that subsequent to a gradual or sequential closing of the ports, a limit of mattress depression is effectively established.